This invention relates to a connection terminal having a neck portion formed between a terminal connection portion and a wire connection portion.
Patent Document 1 discloses a conventional connection terminal. As shown in FIGS. 8 and 9, this conventional connection terminal 100 includes a terminal connection portion 101 for the connection of a mating terminal thereto, a wire connection portion 110 having a wire accommodating space 112 and adapted to be connected to a wire (not shown) disposed in the wire accommodating space 112, and a neck portion 120 disposed between the terminal connection portion 101 and the wire connection portion 110. This connection terminal 100 is formed by bending a single electrically-conductive sheet into a predetermined shape.
The terminal connection portion 101 includes a tubular portion 102 defined by a lower wall 102a, opposite side walls 102b and an upper wall 102c. A resilient contact piece portion 102d is provided within the tubular portion 102. When the mating terminal is inserted into the tubular portion 102, this mating terminal is held in intimate contact with the tubular portion 102 by a reaction force resulting from resilient deformation of the resilient contact piece portion 102d. A rear edge of the upper wall 102c of the tubular portion 102 serves as a lance engagement portion 103. The connection terminal 100 is accommodated in a terminal accommodating chamber of a connector housing (not shown), and a lance provided within the terminal receiving chamber is engaged with the lance engagement portion 103, thereby fixing the connection terminal 100 relative to the connector housing.
The wire connection portion 110 has a surrounding wall 111 of a generally U-shaped cross-section extending continuously from a lower wall 121a and opposite side walls 121b of the neck portion 120, and the wire accommodating space 112 is defined by this surrounding wall 111. A pair of first wire press-fastening portions 113, as well as a pair of second wire press-fastening portions 114, are formed on and project respectively from upper edges of the U-shaped surrounding wall 111. The pair of first wire press-fastening portions 113 are press-fastened onto an exposed portion of a conductor of the wire (not shown) to be fixed thereto, while the pair of second wire press-fastening portions 114 are press-fastened onto a sheath of the wire to be fixed to the wire.
The neck portion 120 includes the lower wall 121a extending continuously from the lower wall 102a of the terminal connection portion 101, and the opposite side walls 121b extending continuously respectively from the opposite side walls 102b of the terminal connection portion 101. The neck portion 120 is formed such that a width W12 of the neck portion 120 between the opposite side walls 121b is decreasing gradually toward the wire connection portion 110.
Namely, in order that the wire connection portion 110, when press-fastened onto the wire, can firmly fix the wire (not shown), it is preferred that the width of the wire accommodating space 112 should be formed into a dimension corresponding to the width of the wire. Therefore, by the provision of the neck portion 120, a width W10 at the tubular portion 102 of the terminal connection portion 101 is reduced or narrowed down into a width W11 at the wire connection portion 110.    [Patent Document] Japanese Patent Publication No. 2007-280825 A
However, in the case where the connection terminal 100 is designed to meet a small-diameter design of the wire (not shown), so that the difference between the width W10 of the tubular portion 102 of the terminal connection portion 101 and the width W11 of the wire connection portion 110 is large, the rate of gradual decrease of a width W12 of the neck portion 120 increases, and therefore a crack or the like is liable to be produced in the connection terminal 100 by a bending force applied during a press-shaping operation for forming the connection terminal 100, thus causing a so-called terminal crack.
Here, in order to prevent such terminal crack, it may be proposed to increase a length L11 (see FIG. 9) of the neck portion 120. In this case, however, the overall length L10 of the connection terminal 100 is increased because of the increased length of the neck portion 120. When the connection terminal 100 is thus increased in size, there arise problems such as an increased cost of the material for the connection terminal 100, an increased size of the connector housing for accommodating the connection terminal and an increased cost of the material for the connector housing.